161215 - Implement quick DER decoder

Status: RESOLVED FIXED

(NSS :: Libraries, defect, P1)

Description

[Julien Pierre]

The ASN.1 DER decoder was shown to perform too many memory allocations which
made performance unbearably slow. Bug # 149816 has more details.

Comment 1

[Julien Pierre]

Attachment: quickder.c - implementation of new quick DER decoder

Updated after Wan-Teh's review

This still needs to be reviewed for functional correctness by someone
knowledgeable of ASN.1 and our templates, in particular MatchItemType and
DecodeItem .

Comment 2

[Julien Pierre]

Attachment: quickder.h - declaration of quick DER decoder

Comment 3

[Julien Pierre]

Attachment: patches for manifest.mn and secasn1t.h

Comment 4

[Julien Pierre]

Checked in the new decoder to the NSS 3.6 tip .

Checking in manifest.mn;
/cvsroot/mozilla/security/nss/lib/util/manifest.mn,v  <--  manifest.mn
new revision: 1.8; previous revision: 1.7
done
RCS file: /cvsroot/mozilla/security/nss/lib/util/quickder.c,v
done
Checking in quickder.c;
/cvsroot/mozilla/security/nss/lib/util/quickder.c,v  <--  quickder.c
initial revision: 1.1
done
RCS file: /cvsroot/mozilla/security/nss/lib/util/quickder.h,v
done
Checking in quickder.h;
/cvsroot/mozilla/security/nss/lib/util/quickder.h,v  <--  quickder.h
initial revision: 1.1
done
Checking in secasn1t.h;
/cvsroot/mozilla/security/nss/lib/util/secasn1t.h,v  <--  secasn1t.h
new revision: 1.6; previous revision: 1.5
done
Checking in secerr.h;
/cvsroot/mozilla/security/nss/lib/util/secerr.h,v  <--  secerr.h
new revision: 1.5; previous revision: 1.4
done
Checking in nss.def;
/cvsroot/mozilla/security/nss/lib/nss/nss.def,v  <--  nss.def
new revision: 1.75; previous revision: 1.74
done

Comment 5

[Julien Pierre]

Attachment: quickder.c - new decoder as initially checked in

1) fixed handling of handling of SEC_ASN1_CHOICE, thanks to Terry
2) fixed handling of implicit tagging
3) optimized the two allocations for the array and items in DecodeGroup into a
single one
4) add type checking for SEC_ASN1_INLINE | SEC_ASN1_OPTIONAL as well as
SEC_ASN1_POINTER | SEC_ASN1_OPTIONAL 
5) add type checking for SEC_ASN1_CHOICE even when not decoding, in particular
if the parent is SEC_ASN1_OPTIONAL (see 4), so that choices can be optional
and/or skipped

Comment 6

[Wan-Teh Chang]

It might be a good idea to just declare SEC_QuickDERDecodeItem
in the existing secasn1.h header and do away with the quickder.h
header.

Comment 7

[Julien Pierre]

Many thanks to Terry for the extensive code review. I have incorporated the
feedback into the source tree. Closing this bug.